The present invention relates generally to the field of hydraulic braking systems, and more particularly to an improved hydraulic brake hose assembly for bicycles.
In recent years, mountain bicycles have become increasingly popular with bicycle enthusiasts throughout the world. These bicycles are ruggedly designed and provide for maximum speed and performance on xe2x80x9coff-roadxe2x80x9d terrain. Mountain bike racing, both amateur and professional, has also grown in popularity, see, e.g.,  less than http://www.mountainbike.com greater than . However, the bicycle industry has been hard-pressed to provide high performance components that satisfy a mountain biker""s stringent speed and durability requirements.
As might be expected, efficient and reliable braking systems are particularly important for mountain bikes. Such braking systems must withstand the friction and heat associated with high speed racing, and the frequent impacts, falls and sloppy riding conditions associated with rugged mountain bike terrain. Hydraulic braking systems for conventional bicycles have been known and used in the past, as shown in U.S. Pat. Nos. 4,391,353 and 4,615,415 to Mathauser, U.S. Pat. No. 5,678,665 to Debreczeni and U.K. Patent 745,061 to DuBois et al. Most prior art hydraulic braking systems for bicycles utilize a plastic brake hose 2 with crimp-type end fittings 4 that are crushed onto or xe2x80x9ccrimpedxe2x80x9d to the brake hose, as shown in FIG. 1. These hose assemblies are limited in several respects. First, the end fittings are not reusable; that is, they cannot be reattached once they are removed. Thus, if a biker needs to remove a brake line in order to bleed, flush or clean the brake system, he or she will have to replace the entire brake hose assembly. Second, presently known brake hose assemblies, which are typically made of relatively weak plastic materials, lack durability, and are, therefore, prone to cracks, nicks, or cuts from the impacts and falls common to mountain biking. These brake hose systems must frequently be replaced, and will often force a racer to withdraw during a race because of mechanical failure. Damaged brake hoses may also allow contaminants, like dirt, sand, mud and water, to enter the brake system and compromise performance. Finally, presently known plastic brake hoses often suffer from diametric expansion due to the heat generated from braking friction (especially harsh under racing conditions), the sun, or outdoor air temperature. The expansion is often referred to as a xe2x80x9cspongyxe2x80x9d brake feeling, which translates to diminished braking performance. As the rider presses on the brake handle or actuator in an attempt to increase the fluid pressure throughout the system, the brake hose will often expand or bubble, increasing the system volume, and, thus, limiting the pressure within the hose, resulting in decreased braking performance.
Therefore, a need exists for an improved hydraulic brake hose assembly that will offer reusability, increased durability, and more consistent braking performance to mountain bike racers. The present invention provides such a brake hose.
The invention is directed to a hydraulic brake hose assembly comprising a tube for carrying fluid, a fiber mesh layer covering the tube, thereby reinforcing and protecting the tube; a first fitting at a first end of the covered tube; a second fitting at a second end of the covered tube; and a coating over the covered tube from the first end to the second end, covering a first point where the first fitting meets the covered tube, and covering a second point where the second fitting meets the covered tube. The coating further protects the covered tube and fittings, and prevents contaminants from entering the tube. The tube may be formed of expanded polytetrafluoroethylene (PTFE), polypropylene, polyvinyl chloride (PVC), polyethylene, rubber or any other suitable material. Preferably, the tube is formed of an expanded polytetrafluoroethylene (PTFE) material, such as TEFLON(copyright). The fiber mesh layer may be formed of a metallic material, such as steel, stainless steel, aluminum, or titanium, or, it may be formed of a suitable non-metallic material, such as carbon fiber, polyamide fiber, such as KEVLAR(copyright), glass fiber (fiberglass), or graphite fiber. The coating may be formed of a polyolefin material, such as polyethylene, or it may be formed of other suitable materials such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or polyurethane. Preferably, the fiber mesh layer is formed of stainless steel and the coating is formed of a shrink-fit polyolefin material. The coating may be transparent or colored to match the surrounding components. While the shrink fit method is preferred, several other coating methods, such as dipping the covered tube or spraying the covered tube, are also applicable.
In a preferred embodiment, the brake hose assembly is reusable, and the first and second fittings are configured and adapted to facilitate removal of the brake hose assembly from a brake system and re-attachment of the brake hose assembly to the brake system. In addition, the first and second fittings may be configured and adapted for removal from the covered tube and replacement on the covered tube. The first fitting may comprise: a cap threaded to accept a screw-type adaptor; an olive; and an adaptor for a master cylinder wherein the cap, olive and adaptor are connected to the covered tube to form a fluid-tight connection between the covered tube and the master cylinder. The second fitting may further comprise a cap threaded to accept a screw-type adaptor; an olive; and an adaptor for a brake caliper wherein the cap, olive and adaptor are connected to the covered tube to form a fluid-tight connection between the covered tube and the brake caliper.
Alternatively, the first and second fittings may be swaged to the covered tube.
In another preferred embodiment of the invention, the brake hose assembly comprises: a flexible tube for carrying fluid; a flexible fiber mesh layer covering the tube, thereby forming a reinforced hose; a first fitting at a first end of the reinforced hose; a second fitting at a second end of the reinforced hose; and a coating over the reinforced hose from the first end to the second end, covering a first point where the first fitting meets the reinforced hose and covering a second point where the second fitting meets the reinforced hose, wherein the coating further protects the reinforced hose and fittings. As in the previous embodiment, the flexible tube may be formed of expanded polytetrafluoroethylene (PTFE), polypropylene, polyvinyl chloride (PVC), polyethylene or rubber. Preferably, the flexible tube is formed of an expanded polytetrafluoroethylene (PTFE), such as TEFLON((copyright). The fiber mesh layer may be formed of a metallic material, such as steel, stainless steel, aluminum, or titanium, or, it may be formed of a suitable non-metallic material, such as carbon fiber, polyamide fiber, such as KEVLAR(copyright), glass fiber (fiberglass), or graphite fiber. The coating may be formed of a polyolefin material, such as polyethylene, or it may be formed of other suitable materials such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or polyurethane. Preferably, the fiber mesh layer is formed of stainless steel and the coating is formed of a shrink-fit polyolefin material. The coating may be transparent or colored to match the surrounding components.
In one specific example of this embodiment, the brake hose assembly is reusable, and the first and second fittings are configured and adapted to facilitate removal of the brake hose assembly from a brake system and re-attachment of the brake hose assembly to the brake system. In addition, the first and second fittings may be configured and adapted for removal from the reinforced hose and replacement on the reinforced hose. The first fitting may comprise: a cap threaded to accept a screw-type adaptor; an olive; and an adaptor for a master cylinder, wherein the first end of the reinforced hose is threaded through the cap, the olive is positioned over the first end of the reinforced hose, thereby preventing removal of the cap from the hose without removal of the olive, and the adaptor comprises threads for connection to the cap, and interfaces with the olive to form a fluid-tight connection between the hose and the master cylinder. The second fitting may comprise: a cap threaded to accept a screw-type adaptor; an olive; and an adaptor for a brake caliper, wherein the second end of the reinforced hose is threaded through the cap, the olive is positioned over the second end of the reinforced hose, thereby preventing removal of the cap from the hose without removal of the olive, and the adaptor comprises threads for connection to the cap and interfaces with the olive to form a fluid-tight connection between the hose and the brake caliper.
Alternatively, the first and second fittings can be swaged to the reinforced hose.
In a further embodiment, the invention is a reusable hydraulic brake hose assembly comprising: a flexible tube for carrying fluid; a flexible fiber mesh layer covering the tube, thereby forming a reinforced hose; a first fitting at a first end of the reinforced hose; a second fitting at a second end of the reinforced hose; wherein the first and second fittings are configured and adapted to facilitate removal of the brake hose assembly from a brake system and re-attachment of the brake hose assembly to the brake system. Again, the flexible inner tube may be formed of expanded polytetrafluoroethylene (PTFE), polypropylene, polyvinyl chloride (PVC), polyethylene or rubber. Preferably, the flexible tube is formed of an expanded polytetrafluoroethylene (PTFE), such as TEFLON(copyright). The fiber mesh layer may be formed of a metallic material, such as steel, stainless steel, aluminum, or titanium, or, it may be formed of a suitable non-metallic material, such as carbon fiber, polyamide fiber, such as KEVLAR(copyright), glass fiber (fiberglass), or graphite fiber. The mesh fiber layer is preferably formed of stainless steel.
In one specific example of this embodiment, the first and second fittings are adapted and configured for removal from the reinforced hose and replacement on the reinforced hose. The first fitting may comprise: a cap threaded to accept a screw-type adaptor, an olive, and an adaptor for a master cylinder, where the first end of the reinforced hose is threaded through the cap, the olive is positioned over the first end of the reinforced hose, thereby preventing removal of the cap from the hose without removal of the olive, and the adaptor comprises threads for connection to the cap and interfaces with the olive to form a fluid-tight connection between the hose and the master cylinder. The second fitting comprises: a cap threaded to accept a screw-type adaptor, an olive, and an adaptor for a brake caliper, where the second end of the reinforced hose is threaded through the cap, the olive is positioned over the second end of the reinforced hose, thereby preventing removal of the cap from the hose without removal of the olive, and the adaptor comprises threads for connection to the cap, and interfaces with the olive to form a fluid-tight connection between the hose and the brake caliper.
The assembly may further comprise a coating over the reinforced hose from the first end to the second end, covering a first point where the first fitting meets the reinforced hose and covering a second point where the second fitting meets the reinforced hose, where the coating further protects the reinforced hose and fittings. Once again, the coating may be formed of a polyolefin material, such as polyethylene, or it may be formed of other suitable materials such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or polyurethane. Preferably, the coating is formed of a shrink-fit polyolefin material. The coating may be transparent or colored to match the surrounding components.